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3.3 revs to high rpms, but wont move

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rc jordy

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hey guys, i went to drive my tmaxx after fixing it and it was working fine for a few mins, then when it was about to hit second gear it revved really high pitch and just coasted as if in neutral, i have checked the slipper clutch and it is tightened all the way, and the gears are lined up perfectly (paper thickness apart)

I'm guessing it must be the tranny, what are any ways to check?

thank you in advance :]
 
can anyone please help me? traxxas support is closed on weekends, and my local hobby shops technician isnt in till monday :[
 
when you start it does the spur gear turn? if so it will be a gear in the transmission.
 
the drive shaft moves if i pick it up off the ground, but not if its on the ground so i dont think its that.

and yes the spur gear turns so i beleive its a gear in the transmission. I'm dreading taking it apart :[

and now when its idleing it starts revving without me pushing the throttle, so i beleive there may be an air leak, but i just put a brand new carb on it so its not that, and i also checked the gas tank lines and they're good.

any ideas as to where the air could be coming in?
 
usually when i burn a gear inside the transmission the motor revs up till i shut it off(quickly as possible). if you set it on the ground and start it the spur gear turns but the drive shafts do not. right? it's in the transmission.
 
if you stripped a gear there is no load on the engine so its going to rev to really high rpms. I'm sure you probably dont have a leak but hey i could be wrong!
 
New carb or not, nitro engines leak. But that's not your main problem at the moment.

Does it drive until it gets enough speed to hit second now? Once it hits second, the engine just rev's?

What exactly did you take apart and fix?
 
i fixed two things, i replaced the carb because the old ones high speed needle slot was stripped.

the second thing i replaced is the clutch bell shoes and spring, as the old ones were shattered.

after i finished installing those two parts, i put it all back together and fired it up. i was taking it easy going up and down the street, warming it up, and when it was about to hit 2nd gear it started coasting and revved really high.

ever since then it wont engage into first gear, it just revs in neutral.

I'm sure its somthing in the transmission.
 
$23 http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHGG4&P=7
Kind of smart how they include a new shaft with a new bearing. A novice may run a new bearing on an old shaft, but with one way bearings, an old worn shaft cuts their lifespan considerably.

They didn't do that on the t-maxx when I bought mine... found out the hard way ;).

For future reference, the same issue applies to engine one way bearings. Any time you replace an OWB because it's worn, you should replace the shaft it spins on as it's probably worn as well.

EDIT:

I'm sorry, that's for the 3.3 revo. Is yours the newer 3.3 maxx or an older 2.5 maxx that has a 3.3 engine in it? The 2.5 maxx trans will require different parts if it's the OWB.

2.5 maxx trans
bearing: http://www3.towerhobbies.com/cgi-bin/wti0095p?FVPROFIL=++&FVSEARCH=4986&search=Go
shaft: http://www3.towerhobbies.com/cgi-bin/wti0095p?FVPROFIL=++&FVSEARCH=4993&search=Go

3.3 maxx (new style trans similar to revo):
Uses same as revo 2.5 and 3.3
Posted above: $23 http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXHGG4&P=7
 
Last edited:
thanx for all the help guys, i think i figured out what was wrong.

where the drive shaft connects to the transmission, the back driveshaft screw was loose, i tightened it, but when i went to start it up it wouldnt, so i checked the carb and I'm pretty sure its clogged but idk, when i screwed the highspeend needle back in it stripped the carb again :o so i have to find time to buy a new one.

I'm hoping they make aluminum ones, because its ridiculous how easy the carbs get stripped.
 
Ok...hands for how many people have stripped the threads in the carb.
The epoxy on the threads is holding it in fine while the lhs has one on order, however the plastic piece that the fuel line connects to is not quite tight enough and it is leaking(rats) I've just gooped a bunch of high temp gastket around it to see if it will hold the pressurefrom the line.
Does anyone make a better carb than this pos?
 
darnoced said:
Ok...hands for how many people have stripped the threads in the carb.
The epoxy on the threads is holding it in fine while the lhs has one on order, however the plastic piece that the fuel line connects to is not quite tight enough and it is leaking(rats) I've just gooped a bunch of high temp gastket around it to see if it will hold the pressurefrom the line.
Does anyone make a better carb than this pos?
Click to expand...

Put the breaker-bars away. They're composite so they don't get hot and boil the fuel. By now you should know what it takes to strip them. Stop just before.
 

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